by ronnietucker @ instructables.com:
So, first thing I did was to get the LCD and keypad working together.
For this I pretended that it was some sort of arm/disarm (or entry/exit) thing.
My code for this part is at: http://pastebin.com/YndLneqm.
Getting the LCD wired up was tricky as most wiring diagrams for it don’t show the last two pins wired up and these are required for the back light. Check my snazzy Fritzing wiring diagram to see how I wired up my LCD screen, pot (for adjusting brightness) and keypad. The pins for them all are also mentioned in my code.
Arduino Laser Trip Wire - [Link]
A group of engineers have developed the smallest organic laser [via] :
The 8-µm-long device, which looks like a suspended bridge riddled with holes, is carved into a silicon chip coated with an organic dye. Integrated into microprocessor chips, such tiny lasers could one day speed up computers by shuttling data using light rather than electrons. They also could be valuable for sensors and lab-on-a-chip devices.
Engineers Build Ultrasmall Organic Laser - [Link]
Here’s a DIY 38mm x 38mm laser engraver build using CD-ROM/writer on ATmega328p by Davide Gironi:
A laser engraving machine, is a tool that uses lasers to engrave an object.
To build this tool I’ve used two old CD-ROM writer that lays around in my garage.
The X/Y positioning system it is build using the CD-ROM motor assembly. For the engraving laser i use the CD-ROM writer laser.
With this hardware the engraving area are will be almost 38mm x 38mm.
A DIY laser engraver build using DVD and CD-ROM/writer - [Link]
What’s inside one of those omni-directional laser barcode scanners you use at the supermarket, and how does it work? Motorola / Symbol LS9208
EEVblog #637 – Omni Directional Laser Barcode Scanner Teardown - [Link]
by Kalle Hyvönen:
Here’s a quick project I made in couple days or so. It is a push-pull step-down laser diode driver based on LT1683 SMPS controller chip from Linear Technology. The circuit works with 12-18V input and can put out about 1A to a 2V load. I used a PL140-105L planar ferrite transformer from Coilcraft which is quite overkill for this application (it is rated for 140W).
Switchmode laser diode driver based on LT1683 - [Link]
Ian D. Miller made a Raspberry Pi powered laser engraver using two old DVD RW drives. He writes:
engravR is a Raspberry Pi powered laser engraver built primarily using two old DVD RW drives. It was built following the following tutorial: http://funofdiy.blogspot.com/2013/10/a-raspberry-pi-controlled-mini-laser.html Note that I did make changes to the code given there in order to allow remote engraving and to be able to read the kind of GCode that GCodeTools generates. It is available at the above GitHub link.
engravR – RPi Laser Engraver - [Link]
joebell @ instructables.com writes:
With a little practice, you can make excellent double-sided PCBs by combining a laser cutter with chemical etching. The basic idea is: the laser cutter blasts away spray painted etch resist, then chemicals eat away the exposed copper. Once the copper is gone, the underlying board can be cut again with the laser to make through-holes. No drilling required! After some setup and practice, you should get reliable boards with 8-mil trace/space and hundreds of holes in about 2 hours. You can even cut internal routing and odd board-shapes!
Double-sided PCBs with a laser cutter - [Link]
You can use this cutter to cut very accurate PCB stencils on your home:
Are you sick and tired of using a tooth pick to apply solder paste? Are you still using through hole components because you don’t want to deal with soldering surface mount devices (SMD)? If so, this post provides you with guidelines for building your very own laser cutter for cutting PCB stencils. With a total cost of approximately $200 (it can be significantly less if you already have parts laying around), this project can pay for itself very quickly. While you can get “low cost” stencils for your PCBs, they still can be quite expensive if you are only creating one or two boards.
DIY Laser Cutter for PCB Stencils - [Link]
What is the biggest constraint in creating tiny lasers? Pump power. Yes sir, all lasers require a certain amount of pump power from an outside source to begin emitting a coherent beam of light and the smaller a laser is, the greater the pump power needed to reach this state. The laser cavity consists of a tiny metal rod enclosed by a ring of metal-coated, quantum wells of semiconductor material. A team of researchers from the University of California has developed a technique that uses quantum electrodynamic effects in coaxial nanocavities to lower the amount of pump power needed. This allowed them to build the world’s smallest room-temperature, continuous wave laser. The whole device is only half a micron in diameter (human hair has on average a thickness of 50 micron). [via]
World’s Smallest Laser Is Smaller Than Dust - [Link]
With the help of the most powerful X-ray laser in the world researchers of the SLAC National Accelerator Laboratory of the U.S. Department of Energy have heated a piece of aluminum to a temperature of two million degrees Celsius (3.6 million degrees Fahrenheit). They also managed to verify the temperature achieved. This work could be an important step to a better understanding of nuclear fusion processes that go on in the cores of stars and giant planets like Jupiter. [via]
3,600,000 F – The Hottest Thing on Earth - [Link]